Quote Originally Posted by dorikin View Post
Throttle cable is fine.. I'll check the TB plate, but if it was slightly open wouldn't that generally cause a higher idle thats steady?

I've had a look around vacuum hoses for leaks but couldn't find any.

I would describe it more as a drop in idle that bounces back up then drops again, etc. Imagine someone putting their hand over your TB which cuts off air and drops the idle to 200rpm, and then takes their hand off which shoots the idle back up and so on.. mine feels something like that.

I'll try and upload a video
Its my understanding that if your rpm is too high when your idleing your ecu will cut the fuel untill the rpm drops, then when it reaches a lower rpm it will turn the fuel back on which will repeat the cycle. This can be caused by too much air getting into the engine weather it be from a vacuum leak, improperly adjusted idle screw, TB plate not sealed etc

If you have ruled out vacuum leaks and you have checked your throttle body is sealing properly i would probably test the IACV next and make sure its still functioning properly.